Often times it becomes desirable to abandon a borehole created in connection with resource exploration and/or extraction operations. There exists a wide array of reasons for closing and abandoning, either temporarily or permanently a borehole. A borehole may not have developed sufficient resources to justify further operations, resources may have, overtime, become depleted, or a myriad of other reasons may exist to justify abandoning a borehole.
When abandoning a borehole, a plug is installed to prevent any leakage. Typically the plug includes a cement column having a desired height ranging from several tens of feet to hundreds of feet. In order to reduce any potential leakage, a portion of an inner casing may be removed. Following removal of the inner casing, cement and other debris is removed up to an outer casing. Removing the inner casing requires running in a milling tool, milling a portion of the inner casing at a particular location, and then withdrawing the milling tool.
With the portion of the inner casing removed, a scraper may be run downhole to clean up any residual cement and other debris out to the outer casing. Once the debris is removed, the scraper is removed and yet another tool is run downhole to perform a cementing operation. Each tool run takes time and resources that add to an overall cost of plugging and abandoning a borehole. Systems that would reduce the number of operations required to plug a borehole would be well received in the industry.